linux-kernel - [PATCH] drm/msm/dp: Free resources after unregistering them

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Message-ID: <20230612220259.1884381-1-quic_bjorande@quicinc.com>
Date:   Mon, 12 Jun 2023 15:02:59 -0700
From:   Bjorn Andersson <quic_bjorande@...cinc.com>
To:     Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>
CC:     Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        "Daniel Vetter" <daniel@...ll.ch>,
        Johan Hovold <johan+linaro@...nel.org>,
        "Vinod Polimera" <quic_vpolimer@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/msm/dp: Free resources after unregistering them

The DP component's unbind operation walks through the submodules to
unregister and clean things up. But if the unbind happens because the DP
controller itself is being removed, all the memory for those submodules
has just been freed.

Change the order of these operations to avoid the many use-after-free
that otherwise happens in this code path.

Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support")
Signed-off-by: Bjorn Andersson <quic_bjorande@...cinc.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index bbb0550a022b..ebc84b8fddf8 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1337,9 +1337,9 @@ static int dp_display_remove(struct platform_device *pdev)
 {
 	struct dp_display_private *dp = dev_get_dp_display_private(&pdev->dev);
 
+	component_del(&pdev->dev, &dp_display_comp_ops);
 	dp_display_deinit_sub_modules(dp);
 
-	component_del(&pdev->dev, &dp_display_comp_ops);
 	platform_set_drvdata(pdev, NULL);
 
 	return 0;
-- 
2.25.1